Bristol Myers Squibb Co. is buying privately held drugmaker Flexus Biosciences Inc. for up to $1.25 billion to add new cancer fighting drugs to its pipeline. The deal includes $800 million in upfront payment and up to $450 million of milestone payments. Bristol Myers also inked a deal with Rigel Pharmaceuticals Inc. to develop a line of cancer therapies than can be used with it’s immunotherapy cancer drugs Opdivo and Yervoy. BM will pay Rigel $339 million including milestones, bringing the firms investment in cancer drugs to $1.59 billion for the day. The Flexus acquisition gives BM the rights to an experimental cancer treatment, which works by disrupting mechanisms through which cancer cells hide from the body’s immune cells. Remaining Flexus’ assets will become part of a newly formed company BM said. Shares for Rigel shot up 43% to $3.65 in premarket trading.